100 microwatts? What does a phone use, like 1W? So they are 4 orders of magnitude off? So phones need to become 10,000 times more efficient or the battery that much bigger?

Edit: Also what is the language of the article? “63 nuclear isotopes”, it sounds like they mean “63 [different/individual atoms of] nuclear isotopes” but do they mean “nickel-63” by this? It is very confusing. Nickel-63 also has a half-life of 100 years, so if the battery is supped to last for 50 years, it has to be producing twice as much energy on day one that is discarded?